................................................................................................................................ 2 ACKNOWLEDGEMENTS ...................................................................................................... 3 STATEMENT OF PERSONAL CONTRIBUTION TO BODY OF WORK CONDUCTED BY THE RESEARCH GROUP ................................................................... 5 PUBLICATIONS ........................................................................................................................ 7 Chapter 1: Introduction ..................................................................................................... 19 1.1 Asthma ......................................................................................................................................................... 19 1.2 Phenotypes and endotypes ................................................................................................................. 20 1.2.1 The use of cluster analysis to identify phenotypes in asthma. .................................... 21 1.2.2 The use of phenotypes to guide asthma management. .................................................. 21 1.2.3 Cluster-derived asthma phenotypes and genetic linkage. ............................................ 22 1.3 Pathogenesis of asthma ........................................................................................................................ 23 1.3.